Process and apparatus for electroplating



PROCESS AND APPARATUS FOR ELECTROPLATING Filed 001:. 24, 1929 z 5.5 2 3 /0 9 I t Fatentecl Feb. 21, 1933 FREDERICK CONLIN, OF NEW YORK, N. Y.

PROCESS AND APPARATUS FOR ELECTROPLATING Application fil d October 24, 1929.--Seria1 No. 401,994.

This invention relates to brushes for electroplating and to a method of electroplating in which said brush is used, and provides improvements therein.

The invention comprises improvements upon the device disclosed in my Patent #1545942.

The invention provides a device or brush of the character described which fulfills the manifold requirements for giving practical and satisfactory service in general use. It provides a durable device. It provides a device and method by-which relatively uniform and constant distribution of current to the surface on which the brush is impressed is obtained. It provides a method and device whereby adjustment of the current density may be simply and reliably obtained. It provides an effective means for distributing current from the anode to the solution in the bristle-mass during working. It provides an effective means of utilizing the bristles as a'means of insulating the anode from cathodes (articles being plated) having surfaces of various contours. It provides a device of simple construction, having replaceable anodes, and simple means for adjusting the anode.

An embodiment of the invention, together with several embodiments of anodes, is illustrated in the accompanying drawing. igs. 2 and 3 also serve for explaining the process.

In said drawing Fig. 1 is a schematic view in elevation of an embodiment of a plating brush or device.

Fig. 2 is a schematic view in elevation of the brush or device shown in its position of use.

Fig. 3 is a diagrammatic view illustrating the impression area of the vbrush or device shown in Fig. 2, and also the effective plating area.

Figs.4and 5; 6 and7; 8 and 9; 10and 11; 12 and 13;-14 and 15; 16 and 17 and 18 and 19; are respectively top' plan views and elevations respectively, of a plurality of forms of anodes.

Referring to said drawing, numeral 1 designates the applying device or brush comprising a bristle-head 2, which is fornied of solution held in the mass suitable bristles or fibers, hog-bristles such as used in paint brushes being commonly used. The brush may be provided with a suitable handle 3, the bristle-head 2 and handle 3 i being conveniently secured together by means of a ferrule 5.

Numeral 7 designates an electrode (anode for plating) positioned amongst the bristles,

and adapted tobe immersed in electrolytic of bristles, which solution is taken up by the brush prior to use of the same. The solution used is preferably a colloidal-containing or viscous-solution, as described in my application Serial No. 264,270, filed March 23, 1928.

The electrode 7 is preferably attached to a rigid stem 9 so as to constitute a rigid structure. The electrode may have various forms, examples of which are hereinafter described. The electrode 7 and its stem 8 are made of substantial construction, so as to resist appreciable bending and deformation under the pressure used in applying the brush in use. Where the electrode (anode) is soluble its substantial constructionenables it to last for a relatively long time. Moreover, most metals subjected to the conditions of an electrode, become corroded and easily broken or deformed, if not of substantial form. The electrode is also liable to embrittlement especially when used as a cathode and hence liable to break if not of substantial form. I

The handle 3 is preferably provided with a longitudinal passage 11 through which the stem 9 passes, and a binding screw 13 passing through a threaded hole in the ferrule 5 and handle 3 serves for binding the stem 9 in passage 11, and thereby holding the electrode in position. The screw 13 provides a very simple means for adjusting the position of 1 the electrode with relation to the free ends of the bristles, as hereinafteiamore fully described.

The preferred form of electrode 7 is illustrated in Figs. 1, 2, 4 and 5. It has the form of a loop or ring, 15, through which a group l of bristles is passed, and around which a ring of bristles is arranged so thatthe electrode 7 cross-wise of the longitudinal direction of the ments,

- in the direction of the ring,

so that when the bristles are flexed they bend around the electrode, as shown in Fig. 2, the bristles outside of the ring bending around the outer periphery and those inside of the ring bending around the inner periphery, the inner part 17 of the ring catching a group of the bristles so that the mass clings thereto, and the construction of the electrode as a whole being such that the bristles will not part when the bristles are pressed against the electrode, and thereby make contact with metal parts against which the brush is applied. Furthermore the ring 15 presents portions cross-wise of the bristles in every direction, so that the brush may be dragged or applied against a surface in any direction and the bristles will still meet a portion of the electrode cross-wise thereof and around which they bend. Arms 19, preferably welded to ring 15 and to stem 9, serve to con-' nect the ring to the stem, and provide a sturdy construction with permanent elecv trical continuity. Rod or wire stock conveniently is used in making the electrodes, and when soluble anodes, are ordinarily of the same metal as that deposited.

The dimension of the electrode lengthwise of the bristles is small, so as to offer no impedance to the flow of liquid from the mass of bristles onone side of the electrode to the mass on the other side, as hereinafter more fully described. In the form shown in Figs. 4 and 5, and in most of the other embodithis dimension is no greater than the diameter of the rod or wire used to form the electrode. This small dimension of the electrode 7, in the direction of thelength of the bristles permits of a long adjustment of the electrode in the bristle-head while maintaining a constant distance from the free ends of the bristles, and leaving a considerable distance from the anode to the secured ends of the bristles;

An embodiment of electrode very similar to that shown in Figs. 4 and 5 is illustrated in Figs. 6 and 7 The stem 9 and ring 15 are formed of a single piece of rod or wire, the end of the rod or wire being bent out and around in the form of a ring having its axis bristles,

' in line with the stem, as shown. The dimension of the ring 15 lengthwise of the bristles is small.

In the embodiment of electrode shown in Figs. 8 and 9, the parts may be formed of rod or wire, the end being looped in a plurality of loops 22, 23, 24 having portions crosswise of the bristles, and also recessed porbent around tions adapted to receive flexed bristles when pressed toward the looped end from any direction. The dimension of the wire and the form offers no impedance to the flow of solution from side to side of the electrode when positioned in the bristle-head.

In Figs. 10 and 11 aring 15 similar to 15Eig. 4 is provided. Arms 19 connect the ring 15 to stem 9. These arms loop down below the lower edge of ring 15 and constitute notches or recesses for receiving masses of the bristles when the brush is impressed on the object in use. istics and action of this embodiment are very similar to those of Figs. 4 and 5.

Figs. 12 and 13 illustrate an electrode in the form of a knob or ball 27. Electrodes of weak structural metals, such as lead, are conveniently made of this form. The form is such that the bristles do not readily part when flexed against the electrode, and recesses 29 may be formed therein to assist the bristles clinging thereto when flexed around the same. permitting flow of liquid from the mass of bristles on one side to the other side, as hereinafter more fully described Figs. 14 to 19 illustrate embodiments of electrodes most suitable for so-called flat. brushes, and adapted to effect clinging of the bristles thereto when the bristles are flexed in one or the other direction as the brush is dragged or applied with one of its broad faces in the direction of advance.

In Figs. 14 and 15 and 16 and 17 the electrode is conveniently formed of rod or wire stock;.in Figs. 14 and 15 the end 35 being and across the axis of the stem 9. A recess 36 may be formed in end 35 to effect clinging. of the bristles thereto in use.

oIn Figs. 16 and 17, two ends 38, 39 may be bent around as shown, with the, ends turned up and brought together, the crotch 40 between the ends constituting a recess for receiving the bristles when the brush is flexed. The form of the electrode offers no" appreciable impedance to flow of solution from one side to the other thereof.

In Figs. 18 and 19 a plate 44 is attached to a stem 9. The lower edge 46 may be curved slightly .upward to form a recess forreceiving the'flexed bristles, as described. The plate 44 is perforated, as indicated at 48, to permit flow of solution from the bristle mass on one side thereof to the other.

The electrodes having the notched or incurved lower edges (as shown in Figs. 8, 11, 13, 15, 17 and 19) are particularly suited to use of the brush in coating pipeand cylin drical or narrow objects.

The exterior of the bristle-head 2, below ferrule 5 is preferably free, so as to admit of distension of the bristles when the brushis impressed, as hereinafter more fully ex- The character- 1, leaving a considerable length of bristle above the anode.

The'brush is made to take up a quantity of electrolyte in suitable manner, so that it is impregnated with the solution preferably well up above the anode. M

The brush is then impressed on the object and dragged or brushed along the object to be plated similarly to the use of a paint brush in applying paint.

The pressure on the brush, and the drag- 1 ging action bends thebristles on the advancing side around the crosswise part or parts of the anode, as indicated in Fig. 2, and the bristles at the following side spread somewhat. The pressure on the advancing side expels the solution from that part of the bristle-mass, and the distension of the bristles on the following side takes up the expelled solution. Under the pressure of applying the brush the anode approaches relatively close to the surface being plated. The bristlemass flexed around and under the anode havmg virtually all of the solution expressed therefrom, acts as an insulator between the anode and the surface immediately. below it. a

The taking up of the solution expressed from the compressed side, fills the voids caused by the distension of the bristles on the following side, and maintains the immersion of the anode in solution and current enters the solution over a relatively wide anode area, and thereby avoids excessive heating and polarization. The dotted line 60 Fig. 2 indicates the area of the bristle-mass around the anode which is well filled with solution. The anode being so formed as not to impede the flow of solution from the bristle-mass on one side' of the anode to the other (the anode being of a small dimension lengthwise of the bristles, or perforated, as already described) permits the ready flow of solution and avoids solution being squeezed out of the bristlemass, and hence provides certain and uniform plating under the pressure-action used in applying the brush. The recesses of one form or another assist in preventing the bristle-mass separating and exposing the anode and thereby making undesirable contacts.

The full line 62, Fig. 3 indicates the impression area, and the dotted line indicates the area well impregnated with the solution and where most of the deposition occurs. The area indicated by dotted line 65 is taken as the effective plating area. By raising the anode, the area 65 is increased; consequently the current density is regulated by regulating the height of'the anode from the free ends of the bristles. Thus, if in the position of the anode shown in Figs. 1-3, the

plating area (65) is 1 square inches, with 3 amperes delivered to the anode, the current density is 2amperes per square inch. If a somewhat less current density is desired, the anode is raised, and vice versa.

As the brush wears, uniform conditions may be maintained by raising the anode to preserve a uniform distance from the anode to the free ends of the bristles. The narrowness of the anode permits successive raising of the anode to compensate for considerable wear at the ends of the bristles.-

The bristle-head is kept well supplied with solution by repeated replenishments, for best results.

The invention may receive other embodi ments than those herein specifically illustrated anddescribed.

What is claimed is:

1. An electroplating implement comprising a bristle-head having a flexible mass of bristles adapted to carry a liquid or viscous electrolytic solution, and an eleetrode located amongst the flexible mass of bristles, said electrode having external portions runnin substantially transversely of the bristles which are concave with relation to a portion of said bristles pressed toward the same when the bristle-head is flexed.

2. An electroplating implement comprising a bristle-head adapted to carry a liquid v or Viscous electrolytic solution, an electrode amongst the bristles of said bristle-head, said electrode having a part running substantially transversely of the bristles adapted to coact with the bristles pressed against it when the bristles are flexed to express solution from the mass of compressed bristles, and holes permitting the solution to pass through the electrode to the other side of the electrode and flood the mass of bristles around the electrode on said opposite side.

3. The method of obtaining substantially uniform current-density in brush electro plating, comprising supplying current from a source having a controlled discharge rate, and regulating the impression area of the bristles when normally flexed until the proper area is obtained to provide the predetermined density of the current'supplied from said. source.

4. An electroplating implement comprising a bristle-head having a flexible mass of bristles adapted to carry a liquidor viscous electrolytic solution, and a rigid electrode located amongst the flexible mass of bristles and comprising a rod or stiff wire having'a looped portion extending amongst the bristles, said loops having concave portions into which tufts of bristles enter, and thereby adapted to prevent the electrode parting the bristles'and coming in contact with the sur- 5 faces operated on.

In wltness whereof, I have hereunto signed my name.

FBEDER-IGK OQNLIN; 

